Rosita Zakeri1, John M Morgan2, Patrick Phillips3, Sue Kitt3, G Andre Ng4, Janet M McComb5, Simon Williams6, David J Wright7, Jaswinder S Gill8, Alison Seed9, Klaus K Witte10, Martin R Cowie11. 1. Imperial College London (Royal Brompton Hospital), United Kingdom; King's College London, United Kingdom. 2. Faculty of Medicine, University of Southampton, United Kingdom. Electronic address: j.morgan@soton.ac.uk. 3. Wessex Cardiology Centre, University Hospital Southampton, United Kingdom. 4. NIHR Leicester Biomedical Research Centre, University of Leicester, United Kingdom. 5. The Newcastle upon Tyne Hospitals NHS Foundation Trust, United Kingdom. 6. Wythenshawe Hospital, Manchester, United Kingdom. 7. Liverpool Heart and Chest NHS Foundation Trust, United Kingdom. 8. Guys and St Thomas' NHS Foundation Trust, United Kingdom. 9. Blackpool Teaching Hospitals NHS Foundation Trust, United Kingdom. 10. University of Leeds and Leeds General Infirmary, United Kingdom. 11. Imperial College London (Royal Brompton Hospital), United Kingdom. Electronic address: m.cowie@imperial.ac.uk.
Abstract
BACKGROUND: Cardiac implanted electronic devices (CIEDs) can detect short durations of previously unrecognised atrial fibrillation (AF). The prognostic significance of device-detected subclinical AF, in the context of contemporary heart failure (HF) therapy, is unclear. METHODS: Amongst patients enrolled in the Remote Monitoring in HF with implanted devices (REM-HF) trial, three categories were defined based on total AF duration in the first year of follow-up: no AF, subclinical AF (≥6 min to ≤24 h), and AF >24 h. All-cause mortality, stroke, and cardiovascular hospitalisation were assessed. RESULTS: 1561 patients (94.6%) had rhythm data: 71 (4.6%) had subclinical AF (median of 4 episodes, total duration 3.1 h) and 279 (17.9%) had AF >24 h. During 2.8 ± 0.8 years' follow-up, 39 (2.5%) patients had a stroke. Stroke rate was highest amongst patients with subclinical AF (2.0 per 100-person years) versus no AF or AF >24 h (0.8 and 1.0 per 100-person years, respectively). In the overall cohort, AF >24 h was not an independent predictor of stroke. However, amongst patients with no history of AF (n = 932), new-onset subclinical AF conferred a three-fold higher stroke risk (adjusted HR 3.35, 95%CI 1.15-9.77, p = 0.027). AF >24 h was associated with more frequent emergency cardiovascular hospitalisation (adjusted HR 1.46, 95%CI 1.19-1.79, p < 0.0005). Neither AF classification was associated with mortality. CONCLUSIONS: In patients with HF and a CIED, subclinical AF was infrequent but, as a new finding, was associated with an increased risk of stroke. Anticoagulation remains an important consideration in this population, particularly when the clinical profile indicates a high stroke risk.
BACKGROUND: Cardiac implanted electronic devices (CIEDs) can detect short durations of previously unrecognised atrial fibrillation (AF). The prognostic significance of device-detected subclinical AF, in the context of contemporary heart failure (HF) therapy, is unclear. METHODS: Amongst patients enrolled in the Remote Monitoring in HF with implanted devices (REM-HF) trial, three categories were defined based on total AF duration in the first year of follow-up: no AF, subclinical AF (≥6 min to ≤24 h), and AF >24 h. All-cause mortality, stroke, and cardiovascular hospitalisation were assessed. RESULTS: 1561 patients (94.6%) had rhythm data: 71 (4.6%) had subclinical AF (median of 4 episodes, total duration 3.1 h) and 279 (17.9%) had AF >24 h. During 2.8 ± 0.8 years' follow-up, 39 (2.5%) patients had a stroke. Stroke rate was highest amongst patients with subclinical AF (2.0 per 100-person years) versus no AF or AF >24 h (0.8 and 1.0 per 100-person years, respectively). In the overall cohort, AF >24 h was not an independent predictor of stroke. However, amongst patients with no history of AF (n = 932), new-onset subclinical AF conferred a three-fold higher stroke risk (adjusted HR 3.35, 95%CI 1.15-9.77, p = 0.027). AF >24 h was associated with more frequent emergency cardiovascular hospitalisation (adjusted HR 1.46, 95%CI 1.19-1.79, p < 0.0005). Neither AF classification was associated with mortality. CONCLUSIONS: In patients with HF and a CIED, subclinical AF was infrequent but, as a new finding, was associated with an increased risk of stroke. Anticoagulation remains an important consideration in this population, particularly when the clinical profile indicates a high stroke risk.